ACTH and hCG stimulation of steroidogenesis is thought to be mediated by cyclic AMP. Recent studies have cast doubts on this theory. This proposal is designed to determine what physiological role cyclic AMP has as a mediator of hormone induced steroidogenesis. To do this we will examine the role of protein kinase as mediators of hormonal and cyclic AMP induced steroidogenesis in normal and neoplastic adrenal testes cells. Further, we will test the influence of inhibitors of adrenyl cyclase on hormone induced steroidogenesis quantitatively. We will also determine whether enzymatic or chemical modification of the adrenal and testes cells influences the ability of the hormone to induce steroidogenesis in a distinct manner from which it stimulates cyclic AMP accumulation. The discrepancies recently observed between stimulation of steroidogenesis and cyclic AMP accumulation may be due to the fact that separate cells in the cell population may respond to hormonal treatment in different fashions. Experiments are designed to measure steroidogenesis and cyclic AMP production in single cells and to determine if the response to the hormones occurs in an all-or-none fashion.